North Carolina expanded the inquiry into its football program to include allegations of academic impropriety involving a former tutor writing papers for players, sources said Thursday.

The Tar Heels relegated at least nine players to the scout team on Wednesday due to the academic portion of the probe, the sources said. The group included players who were questioned as part of the NCAA's inquiry related to agents and trips to Miami.

Sources said starting defensive tackle Marvin Austin, starting defensive end Robert Quinn and starting linebacker Bruce Carter were among the players who were relegated to the scout team. A source said Friday that starting cornerback Kendric Burney also is involved.

Sources said the tutor in question also has been a nanny for coach Butch Davis' family. A source said Friday that e-mails from the tutor showed interaction with players in helping them with papers.

Athletic director Dick Baddour declined to identify the players or say how many may be involved, and he refused to specify what the possible violations may have been, saying only that they involved "a student tutor and student-athletes on the football team.

"We are looking into improprieties that existed outside the classroom," Baddour said. "That's about as close to that as I can get."

The announcement came nine days before the No. 18 Tar Heels' opener against No. 21 LSU in Atlanta, and roughly two months after the NCAA began an investigation into whether two key players -- Austin and receiver Greg Little -- received improper benefits from agents. Defensive line coach John Blake's longtime friendship with California-based agent Gary Wichard also has drawn the NCAA's interest.

Two sources who were interviewed by the NCAA said that Austin has said Miami Dolphins cornerback Vontae Davis helped fund some of his expenditures to South Florida. A source close to Davis says he is good friends with Austin, but hasn't interviewed with the NCAA. The same source says Davis says he didn't pay for Austin's trips.

Joint interviews conducted by NCAA and school investigators during that probe led them to a player who "raised an issue that we felt like deserved further consideration on our part.

"It led us down a road that brought us to what we're talking about," Baddour said.

While the investigation is centered on the football program, Baddour said that "we will certainly use the opportunity to take a complete look at everything that we're doing in the academic support program."

Davis declined to identify the tutor in question except to say she was one of the five his family had hired since their 2007 arrival in Chapel Hill to serve as an academic coach and advisor for his teenage son.

"This is someone that obviously worked with our son," Davis said. "To be honest with you, I think we're really surprised and possibly disappointed, but there's been no revelation as to exactly the extent or what has actually transpired."

Baddour declined to provide additional details about the tutor, except to say that "the person was in [the university's] employ. When we found out about the issues, the tutor was not in our employ."

Baddour said the university has assembled a team to investigate the academic questions. While there is no timetable to resolve that aspect of the probe, "it is likely that the review would extend beyond the start of the season," he said.

If that happens, he said the school will decide if those players will play against LSU, and Baddour said that decision could come as late as game day.

"The investigation now has two prongs, so I want to caution you against making assumptions if student-athletes don't play," Baddour said.

Davis did acknowledge that starting on Monday, he moved some players around the depth chart as part of a contingency plan in case they aren't permitted to play. He did not specify which players have risen or fallen.

"Before the start of training camp, because there was speculation on some of these issues, we made a statement ... that there would come a point in time in preparation for this first game where we would have to prepare with the players that we assumed that we would be able to compete and play with," Davis said. "That's what we've done."

Chancellor Holden Thorp -- who began the news conference by saying "to everyone who loves this university, I'm sorry about what I have to tell you" -- vowed that administrators are taking the probe seriously but expressed hope that its scope ultimately would be limited.

"We will find out what happened. We will do everything we can to keep it from happening again," he said. "And we will not let these mistakes define our university and what we stand for."

Joe Schad is a college football reporter for ESPN. Information from The Associated Press contributed to this report